Publication number | US7680296 B2 |
Publication type | Grant |
Application number | US 10/558,923 |
PCT number | PCT/JP2004/012159 |
Publication date | Mar 16, 2010 |
Filing date | Aug 18, 2004 |
Priority date | Aug 22, 2003 |
Fee status | Paid |
Also published as | EP1657908A1, EP1657908A4, EP1657908B1, US20070127769, WO2005020563A1 |
Publication number | 10558923, 558923, PCT/2004/12159, PCT/JP/2004/012159, PCT/JP/2004/12159, PCT/JP/4/012159, PCT/JP/4/12159, PCT/JP2004/012159, PCT/JP2004/12159, PCT/JP2004012159, PCT/JP200412159, PCT/JP4/012159, PCT/JP4/12159, PCT/JP4012159, PCT/JP412159, US 7680296 B2, US 7680296B2, US-B2-7680296, US7680296 B2, US7680296B2 |
Inventors | Hisashi Inoue, Masataka Ejima, Kenichi Noridomi, Takashi Katsura, Shugo Horikami |
Original Assignee | Panasonic Corporation |
Export Citation | BiBTeX, EndNote, RefMan |
Patent Citations (9), Non-Patent Citations (2), Referenced by (1), Classifications (6), Legal Events (6) | |
External Links: USPTO, USPTO Assignment, Espacenet | |
The present invention relates to an information embedding device which embeds embedment information in vector data and an art related thereto.
Demand of an electronic map is increasing with the spread of a car navigation system and the Internet. To a digital content such as the electronic map, a copy can be created easily. Accordingly, an illegal copy is increasing and protection of copyrights poses an important problem.
Document 1 (published Japanese Patent Application Laid-Open No. 2001-78019) discloses the following information embedding method.
The information embedding method disclosed in the document 1 is explained using
First, a reference point S is calculated from an embedding target point A. More specifically, the reference point S is calculated by masking lower digits of the coordinate of the embedding target point A according to embedment information.
A slashed area of
Moreover, the slashed area of
That is, in the case of the embedment information “1”, the embedding target point A is moved to a point B of
In reading the embedment information (“1” or “0”), the reference point S is calculated, and the area α (
Moreover, document 2 (published Japanese Patent Application Laid-Open No. 2002-300374) discloses the following art.
First, as shown in
Next, based on the x-coordinates of the reference points A and B, a distance between the reference points A and B is divided into n equal parts (here n=5), and 1-bit information is embedded in each section.
Here, when information “0” is embedded, the number of points within the section is made to be even. When information “1” is embedded, the number of points within the section is made to be odd.
In reading the embedment information, in the same manner as mentioned above, each section is determined whether a value of the embedment information is “1” or “0” is determined by whether the number of the points within these sections is either even or odd.
The documents 1 and 2 do not expect a case where the x-y coordinate system changes between the time of embedding information and the time of reading information, and do not meet the case where the x-y coordinate system changes. Therefore, when a rotation operation of a figure is performed between the time of embedding the information and the time of reading the information, it becomes impossible to read correctly the embedment information only from vector data after the operation.
This point becomes remarkable when a rotation operation occurs frequently, like in a case of the map data, and, as a matter of fact, the methods of the documents 1 and 2 cannot be applied to vector data with such a property.
An object of the present invention is to provide an information embedding device which can cope with a rotation operation of vector data.
A first aspect of the present invention provides an information embedding device, comprising: an extracting unit operable to extract information of vertices composing a polygon from vector data including information of the polygon; and an information embedding unit operable, utilizing the information of vertices extracted by the extracting unit, to embed embedment information into the vector data in a robust manner against rotating operation.
According to the present structure, even when the vector data has undergone the rotation operation, the embedment information is held, and trouble is not produced when the embedment information is read out later.
A second aspect of the present invention provides the information embedding device as claimed in the first aspect, wherein the information embedding unit operates, according to the embedment information, a total number of points of the polygon that the embedment information has been embedded.
According to the present structure, the total number of the points of the polygon does not change when the polygon rotates. Even when a malicious third person moves the point of the polygon in order to nullify the embedment information, no trouble may occur in reading the embedment information later.
A third aspect of the present invention provides the information embedding device as claimed in the first aspect, wherein the information embedding unit operates, according to the embedment information, a distance between specified points of the polygon that the embedment information has been embedded.
According to the present structure, the distance between specific points of the polygon does not change, even when the polygon rotates. Therefore, no trouble may occur in reading the embedment information later.
A fourth aspect of the present invention provides the information embedding device as claimed in the first aspect, wherein the information embedding unit changes, according to the embedment information, a number of points that exist on sides of the polygon.
According to the present structure, the total number of the points of the polygon changes.
A fifth aspect of the present invention provides the information embedding device as claimed in the first aspect, wherein the information embedding unit inserts a point on a side of the polygon.
According to the present structure, a shape of the polygon does not change after the point is inserted.
A sixth aspect of the present invention provides the information embedding device as claimed in the first aspect, wherein the information embedding unit inserts a point at a position apart from a side of the polygon.
According to the present structure, a shape of the polygon can be made distorted by inserting the point.
A seventh aspect of the present invention provides the information embedding device as claimed in the first aspect, wherein the information embedding unit changes a number of points that exist on sides of the polygon in a manner such that a remainder value and a value M of the embedment information have a fixed correspondence, the remainder value being a remainder value where a number of points existing on sides of the polygon is divided by a constant number N, wherein the constant number N is an integer not less than a value of 2 and the value M is a non-negative integer less than the constant number N.
An eighth aspect of the present invention provides the information embedding device as claimed in the seventh aspect, wherein the fixed correspondence is a relationship that the remainder value equals to the value M of the embedment information.
A ninth aspect of the present invention provides the information embedding device as claimed in the fourth aspect, wherein the information embedding unit comprises: a constant information inputting unit operable to input a constant number N (N is an integer not less than a value of 2); a remainder calculating unit operable to calculate a remainder where a number of vertices extracted by the extracting unit is divided by the constant number N; an inserting number determining unit operable to determine a number of points to be inserted on a side of the polygon in a manner such that the remainder calculated by the remainder calculating unit and the embedment information have a fixed correspondence; and an insertion executing unit operable to insert points as many as the number determined by the inserting number determining unit into the polygon.
According to these structures, the embedment information can be easily specified by the correspondence between the value of the remainder and the value of the embedment information.
A tenth aspect of the present invention provides the information embedding device as claimed in the first aspect, wherein the constant number N is a constant number that does not depend on a number of vertices of the polygon.
According to the present structure, whatever the number of sides of the polygon is, the embedment information can be embedded by a constant rule.
An eleventh aspect of the present invention provides an information reading device, comprising: an extracting unit operable to extract points on a polygon from embedment information-embedded vector data; and an information reading unit operable to read the embedment information according to a number of the points extracted by the extracting unit and a predetermined rule.
A twelfth aspect of the present invention provides the information reading device as claimed in the eleventh aspect, wherein the predetermined rule is a rule that a remainder value and a value of the embedment information have a fixed relationship, the remainder value being a remainder value where a number of points extracted by the extracting unit is divided by a constant number N (N is an integer not less than a value of 2).
A thirteenth aspect of the present invention provides the information reading device as claimed in the twelfth aspect, wherein the fixed relationship is a relationship that the remainder value equals to the value of the embedment information.
According to these structures, the embedment information which is not lost by a rotation operation can be read certainly.
A fourteenth aspect of the present invention provides the information reading device as claimed in the eleventh aspect, wherein the information reading unit comprises: a number calculating unit operable to calculate a number of the points extracted by the extracting unit; a constant information inputting unit operable to input a constant number N (N is an integer not less than a value of 2); a remainder calculating unit operable to calculate a remainder where the number calculated by the number calculating unit is divided by the constant number N; and an information reading unit operable to read the embedment information according to the remainder calculated by the remainder calculating unit.
According to the present structure, the embedment information can be specified based on the remainder.
A fifteenth aspect of the present invention provides the information embedding device as claimed in the first aspect, wherein the information embedding unit changes a representative point that has been determined concerning the polygon in a manner such that a correspondence among a plurality of geometrical elements of the polygon changes.
A sixteenth aspect of the present invention provides the information embedding device as claimed in the fifteenth aspect, wherein the representative point includes a vertex of the polygon.
A seventeenth aspect of the present invention provides the information embedding device as claimed in the fifteenth aspect, wherein the plurality of geometrical elements are selected from a group consisting of a diagonal of the polygon, a center of gravity of the polygon, a vertex of the polygon, and a representative point of the polygon.
According to these structures, the embedment information can be embedded in the polygon reflecting the geometric property of the polygon.
An eighteenth aspect of the present invention provides the information embedding device as claimed in the seventeenth aspect, wherein the diagonal of the polygon is the longest diagonal.
A nineteenth aspect of the present invention provides the information embedding device as claimed in the eighteenth aspect, wherein the information embedding unit changes the representative point in a manner such that the longest diagonal keeps longest nature.
According to the present structure, it is easy to specify a diagonal which is to be targeted.
A twentieth aspect of the present invention provides the information embedding device as claimed the fifteenth aspect, wherein the correspondence is expressed using a distance between the plurality of geometrical elements.
According to the present structure, the correspondence can be expressed in terms of the distance.
A twenty-first aspect of the present invention provides the information embedding device as claimed in the fifteenth aspect, wherein the information embedding unit comprises: a correspondence determining unit operable to determine a correspondence between a value of the embedment information and the plurality of geometrical elements; and an embedding unit operable to change the representative point according to the correspondence determined by the correspondence determining unit.
A twenty-second aspect of the present invention provides the information embedding device as claimed in the fifteenth aspect, wherein the representative point is a center of gravity of the polygon.
According to the present structure, the embedment information can be embedded in the polygon reflecting the geometric property of the polygon.
A twenty-third aspect of the present invention provides the information embedding device as claimed in the fifteenth aspect, wherein the representative point indicates a facility location.
According to the present structure, the embedment information can be embedded in a polygon without changing a shape of the polygon.
Hereinafter, embodiments of the present invention are described with reference to the accompanying drawings.
Hereinafter, Embodiment 1 of the present invention is explained with reference to the accompanying drawings.
As shown in
The extracting unit 1 inputs the vector data which includes information of a polygon, and extracts, from the vector data, the information of plural vertices which constitutes the polygon.
The constant information inputting unit 3 inputs a constant N (an integer equal to or greater than 2).
The remainder calculating unit 5 calculates a value of a remainder of the number of the extracted vertices when divided by the constant N determined by the constant information inputting unit 3. The inserting number determining unit 4 determines the number of insertion points to be inserted into the polygon such that the value of the remainder calculated by the remainder calculating unit 5 and a value of the embedment information may have a fixed correspondence (both values are equal in the present embodiment).
The insertion executing unit 6 inserts, on a side of the extracted polygon, as many insertion points as the number determined by the inserting number determining unit 4, thereby embedding the embedment information.
As shown in
At Step 12, the constant information inputting unit 3 inputs a constant N.
At Step 13, the remainder calculating unit 5 calculates a value of the remainder of the number of the extracted vertices when divided by the constant N. At Step 14, the inserting number determining unit 4 sets the value of the remainder to a value of embedment information.
The insertion executing unit 6 determines a side on which the insertion points are inserted at Step 15, and inserts as many points as what to be inserted on the side of the extracted polygon at Step 16, thereby embedding the embedment information.
In addition, the constant N inputted at Step 12 is used as key information in reading the embedment information.
In the present embodiment, the extracted polygon is a quadrangle and embedment information is embedded by inserting a point on a side of the quadrangle.
Now, it is assumed that the constant N=N0 and the embedment information M=M0. Here, the number of points to be inserted is determined such that the value of the remainder of the sum of the number of points to be inserted and the number of the vertices of the extracted polygon “4”, divided by N0 is equal to M0. That is, the embedment information M0 is embedded by inserting M0 pieces of points.
In the present embodiment, the fixed correspondence that the value of the remainder and the embedment information M0 are equal is used. However, the fixed correspondence is not limited to this example, but the fixed correspondence may be changed arbitrarily as long as one can be uniquely determined by the other. For example, if N0=4 and M0=2, two points may be inserted.
In the present embodiment, points are inserted as follows.
That is, the points are inserted on three sides of P1P2, P2P3, and P3P4, respectively among four sides of the polygon P1P2 P3P4 shown in
At this time, as shown in
The extracted polygon may be a concave polygon as shown in
Here, the number of the vertices of the extracted polygon is Z, a constant is N, the number of insertion points is Q, and the sum of Z and Q is W. The value of embedment information is M.
When such a correspondence among values Z, N, M, Q, and the value of the remainder exists, the value Q changes as the value M changes.
When an extracted polygon is a quadrangle and a constant N has a value of 4,
In
Next, a case where an extracted polygon is a pentagon is explained. The present invention is similarly applicable to a polygon more than a pentagon, such as a hexagon.
The pentagon of
For the pentagon as shown in
Values M, Z, Q, W, and the remainder of
When an extracted polygon is a pentagon and a constant N=4,
In
Therefore, as shown in
Here, the remainder of W of a value “7” divided by N of a value “4” is “3”, a value of the embedment information M is “3”, and the number of insertion points Q is “2.” Therefore, as shown in
The present embodiment can be changed as follows.
(Modification point 1) A correspondence between remainder and embedment information may be changed.
(Modification point 2) When there is no object to embed on a side of a polygon, an insertion point may be inserted in a location apart from the side.
According to the present embodiment, there is the following effectiveness.
(Effectiveness 1) It is not necessary to set up a reference parameter and a variable parameter like the conventional example.
(Effectiveness 2) By inserting a point on a side of a polygon, changing of a shape of the polygon before and after insertion can be suppressed.
(Effectiveness 3) Even when a malicious third person tries to move one or more vertices among the vertices which constitute a polygon, to falsify vector data and to erase embedment information, such an operation can be made ineffective. It is because the number of vertices cannot be changed even when the malicious third person moves the vertices of the polygon and there is no problem in holding the embedment information and subsequent reading.
As shown in
The extracting unit 10 extracts a polygon from vector data in which embedment information is embedded and further extracts vertices of the extracted polygon.
The number calculating unit 12 calculates the number of vertices of the polygon.
The constant information inputting unit 13 inputs a constant N which is an integer of two or more.
The remainder calculating unit 14 calculates a remainder by dividing the number calculated by the number calculating unit 12 with the constant N which is inputted by the constant information inputting unit 13.
The reading unit 15 reads embedment information from this remainder.
At Step 20, the extracting unit 10 extracts a polygon from vector data.
At Step 21, the number calculating unit 12 calculates the number of vertices of the extracted polygon.
At Step 22, the constant information inputting unit 13 inputs a constant N.
At Step 23, the remainder calculating unit 14 calculates a remainder of the number of vertices divided by the constant N.
At Step 24, the reading unit 15 reads embedment information based on this remainder.
Here, it is defined that the number of points which exist on sides of the extracted polygon is W, and that a value of embedment information is M. Corresponding to Embodiment 1, tables shown in
For example, when the number W of vertices of the extracted polygon is “5”, a value of the remainder R calculated by the value N of “4” is “1”, and the reading unit 15 reads that a value of the embedment information M is “1” using the correspondence of
Moreover, the number of vertices of the polygon before insertion is “4”, and
According to the present embodiment, there is the following effectiveness.
(Effectiveness 1) Embedment information can be read using the correspondence shown in
(Effectiveness 2) Since the correspondence including the number of vertices of the polygon is used as shown in
Furthermore, each component of the information embedding device and the information reading device, according to Embodiments 1 and 2 or all the other Embodiments to be mentioned later, can be constructed as a program, can be installed in a computer, or can be made it circulated via a network.
As shown in
When a CPU 25 executes this program accessing a ROM 26, a RAM 27, and the hard disk 28, the information embedding device and the information reading device in each embodiment mentioned above are realized.
Similar to Embodiment 1, the extracting unit 41 inputs vector data, and extracts vertices of a polygon included in the vector data.
Regarding a plurality of geometrical elements, the correspondence determining unit 43 determines the correspondence between the value of embedment information and the plurality of geometrical elements. The plurality of geometrical elements are chosen from a group that consists of a diagonal of the polygon, a center of gravity of the polygon, vertices of the polygon, and a representative point of the polygon. In the present embodiment, the diagonal of the polygon and the center of gravity of the polygon are chosen.
The correspondence of the geometrical elements can be expressed by either one of “distance between the diagonal of the polygon and the center of gravity of the polygon”, “distance between the diagonal of the polygon and the representative point of the polygon” and “distance between the center of gravity of the polygon and the representative point of the polygon”.
In the present embodiment, the correspondence is expressed by “distance between the diagonal of the polygon and the center of gravity of the polygon”.
When embedment information is binary, a threshold T is defined for a distance chosen from the plurality of distances mentioned above. It is assumed that if the chosen distance mentioned above is shorter than T, information “0” is embedded; and if the chosen distance mentioned above is longer than T, information “1” is embedded. This is the correspondence of the present embodiment.
The embedding unit 44 performs embedding by changing the representative point of the polygon based on the correspondence determined by the correspondence determining unit 43. The representative point may be a vertex and a point that does not indicate the geometric property of the polygon (for example, a point only attached to the polygon). The representative point in the present embodiment is the center of gravity of the polygon.
At Step 32, the correspondence determining unit 43 determines the center of gravity and the longest diagonal of the polygon as geometrical elements of the polygon. At Step 33, the correspondence determining unit 43 determines the coordinates of the center of gravity and the longest diagonal of the extracted polygon.
At Step 34, the correspondence determining unit 43 inputs embedment information, and determines the correspondence between the embedment information and the geometrical element at Step 35. At Step 36, when the embedment information is “0”, the correspondence determining unit 43 defines the coordinates of a specific vertex among the vertices of the polygon, in order to make the distance between the center of gravity of the polygon and the longest diagonal shorter than the threshold T (the distance is zero in the present embodiment). At Step 36, when the embedment information is “1”, the correspondence determining unit 43 defines the coordinates of the specific vertex among the vertices of the polygon, in order to make the distance between the center of gravity of the polygon and the longest diagonal longer than the threshold T.
In addition, the advantage of choosing the longest diagonal is being able to uniquely specify a diagonal except for a case where a plurality of diagonals of the same length exist.
When the polygon is a quadrangle, the plurality of geometrical elements in the present embodiment are the longest diagonal of the quadrangle and the center of gravity of the quadrangle. In the quadrangle P1P2P3P4 of
As arrangement information of the geometrical elements, the distance between the center of gravity G and the longest diagonal P1P3 is determined. The distance between the center of gravity G and the longest diagonal P1P3 is a length from the center of gravity G to a foot H of a perpendicular dropped from the center of gravity G to the longest diagonal P1P3.
Here, this distance is determined using the following formula.
GH=((X _{G} −X _{H})^{2}+(Y _{G} −Y _{H})^{2})^{1/2} (Formula 1)
Generally the range of the value that this distance can take is an arbitrary real number equal to or greater than “0”. Here, it is assumed that the embedment information is “0” or “1”, and the threshold T is introduced (T=1 in the present embodiment).
It is further assumed that, when the embedment information is “0”, this distance is shorter than the threshold T; and when the embedment information is “1”, this distance is longer than the threshold T.
More concretely, a vertex related to the distance between the center of gravity G and the longest diagonal P1P3 (the vertex P2 in an example of
The present embodiment can be changed as follows.
(1) The vertex is controlled so as to change the center of gravity while the location of the longest diagonal is maintained. To the contrary, the vertex may be controlled so as to change the location of the diagonal (but keeping the longest nature) while the location of the center of gravity is maintained.
(2) The embedment information (“0”, “1”) may be replaced.
(3) Although the value of the threshold T is set to “1”, the value can be substituted by an arbitrary value equal to or greater than “0”, instead of “1”.
(4) In the example of
When using the center of gravity G1, the center of gravity is determined without using the vertex P2 that partially constitutes a polygon. Or when using the center of gravity G2, the center of gravity is determined using virtual vertices Q1 and Q2 that are not originally included in the vertices that constitute the polygon.
When the polygon is an octagon P5P6P7P8P9P10P11P12 shown in
When using the center of gravity G3, the center of gravity is determined by not using the vertices P5, P6, P7, P8, P9, and P10 that partially constitute the polygon, but using virtual vertices Q3 and Q4 that are not vertices of the polygon originally. Or when using the center of gravity G4, the center of gravity is determined without using the vertices P6, P7, P8, and P9 that partially constitute the polygon.
In any case, when determination of the center of gravity to be used, is defined uniquely, the determination of the center of gravity is set up arbitrarily. This point is similarly applicable to each embodiment mentioned later.
The extracting unit 51 inputs vector data (in which, embedment information according to Embodiment 3 is embedded) including the information of a polygon, and extracts the information of vertices that constitute the polygon from the vector data.
Next, the correspondence examining unit 53 examines the same correspondence as the correspondence determining unit 43 of Embodiment 3 uses. The geometrical elements in the correspondence are the center of gravity and the longest diagonal of the polygon. Of course, regarding the threshold T, the same threshold T as in Embodiment 3 is used here. In other words, the correspondence examining unit 53 determines the distance between the center of gravity and the longest diagonal of the polygon, and outputs the distance to the reading unit 54.
The reading unit 54 compares the distance and the threshold T which the correspondence examining unit 53 has determined, and reads the embedment information based on the comparison result. More concretely, when the distance is smaller than the threshold T, the information “0” is read. When the distance is greater than the threshold T, the information “1” is read.
At Step 42, the correspondence examining unit 53 chooses the center of gravity and the longest diagonal of the polygon as the geometrical elements, and determines the center of gravity and the longest diagonal of the polygon at Step 43. At Step 44, the correspondence examining unit 53 examines the above-mentioned correspondence, calculates the above-mentioned distance, and outputs the distance to the reading unit 54.
At Step 45, the reading unit 54 performs the above-mentioned great-and-small comparison. As the result, the embedment information (“0” or “1”) is read.
As shown in
As shown in
In addition, in Embodiments 1 and 2, when the range for the value of the embedment information is changed, it is also extensible to multiple values other than binary (“0” and “1”). For example, it is assumed that geometrical elements are a diagonal and the center of gravity, and N pieces of the embedment information (N is integer equal to or greater than two) are “0”, “1” . . . “N−1.” Moreover, it is assumed that arrangement information of geometrical elements is distance between the two geometrical elements, that is, the information regarding the distance between the diagonal and the center of gravity. It is also assumed that the distance is expressed by d (d is a real number equal to or greater than zero). At this time, it is sufficient enough to define each correspondence such that “information “0” is embedded” corresponds to “an arrangement state of the diagonal and the center of gravity where d is equal to or greater than 0 and smaller than 1/N”, “information “1” is embedded” corresponds to “an arrangement state of the diagonal and the center of gravity where d is equal to or greater than 1/N and smaller than 2/N”, . . . , and “information “N” is embedded” corresponds to “an arrangement state of the diagonal and the center of gravity where d is equal to or greater than (N−1)/N.”
According to Embodiment 2, there is the following effectiveness.
(Effectiveness 1) By changing the range of the value of the embedment information, it is extensible to multiple values other than binary (“0” and “1”).
(Effectiveness 2) Since reading uses arrangement state of the geometrical elements, the resistance to rotation operation is high.
The present embodiment can be changed as follows.
(1) Embedment information (“0”, “1”) may be replaced.
(2) Although the value of the threshold T is set to “1”, the value can be substituted by an arbitrary value equal to or greater than “0”, instead of “1.”
The correspondence determining unit 63 chooses a geometrical element from a group which is constituted by a diagonal of the polygon, a center of gravity of the polygon and a representative point of the polygon, and determines correspondence of the chosen geometrical element with the arrangement information. In the present embodiment, it is assumed that the representative point is a facility location that is not directly related to the geometric property of the polygon. Here, for example, the facility means buildings, such as a house, a school, a hospital and so on. The facility location is a location where a name or an acronym of the facility, the appearance of which is shown by the polygon, is expressed in relation to the polygon.
Moreover, the geometrical element of the present embodiment is the center of gravity of the polygon. The correspondence is expressed by the distance between the center of gravity G and the facility location of the polygon. Regarding the distance, a threshold T similar to Embodiment 1 is defined (T=1 in the present embodiment). It is assumed that when the information “0” is embedded, the distance is set to be equal to or smaller than the threshold T; and when the information “1” is embedded, the distance is set to be greater than the threshold T. In addition, the correspondence determining unit 63 operates, in operating the distance, the facility location rather than the center of gravity G, the vertex, and so on.
At Step 52, the correspondence determining unit 63 chooses the center of gravity of the polygon as the geometrical element, and chooses the facility location as the representative point of the polygon. At Step 53, the correspondence determining unit 63 calculates the distance between the center of gravity and the facility location of the polygon.
At Step 54, the correspondence determining unit 63 inputs the embedment information, and determines the facility location of the extracted polygon according to the value of the embedment information that is inputted at Step 55. The correspondence determining unit 63 sets the distance to be equal to or smaller than the threshold T when embedding the embedment information “0”; and sets the distance to be greater than the threshold T when embedding the embedment information “1”. The embedding unit 64 moves the facility location of the polygon to the facility location that is determined at Step 55. Thereby, the embedment information is embedded.
The center of gravity G of the quadrangle P1P2P3P4 of
According to the present embodiment, reference is unnecessary while it was necessary in the conventional example.
The present embodiment may be changed as follows.
(1) Although the center of gravity is chosen as one of two geometrical elements, the diagonal may alternatively be chosen as one of two geometrical elements; thereby the embedment information can be embedded by the same operation.
(2) The embedment information (“0”, “1”) may be replaced.
(3) Although the coordinates of the facility location is changed, the location of the center of gravity may be changed instead. However, when changing the center of gravity, the shape of the quadrangle is changed since the coordinates of the vertex of the quadrangle are changed. Therefore, it is desirable to change the facility location.
(4) Although the value of the threshold T is set to “1”, the value can be substituted by an arbitrary value that is equal to or greater than “0”, instead of “1”.
The extracting unit 71 inputs the vector data (the embedment information is embedded according to Embodiment 5) including the information of the polygon, and extracts, from the vector data, the information of the vertices that constitute the polygon.
The correspondence examining unit 73 examines the same correspondence as in Embodiment 5. More concretely, the correspondence examining unit 73 calculates the distance between the center of gravity and the facility location, and outputs the distance to the reading unit 74. Of course, the same threshold T as in Embodiment 5 is used here.
The reading unit 74 reads the embedment information. More concretely, when the above-mentioned distance is equal to or smaller than the threshold T, the reading unit 74 reads the embedment information “0”. When the above-mentioned distance is greater than the threshold T, the reading unit 74 reads the embedment information “1”.
At Step 60, the extracting unit 71 extracts a polygon from the inputted vector data, and extracts the vertices of the polygon at Step 61.
At Step 62, the correspondence examining unit 73 chooses the center of gravity of the polygon as a geometrical element, and chooses the facility location as a representative point of the polygon. At Step 63, the correspondence examining unit 73 calculates the distance between the center of gravity and the facility location of the polygon, and examines the correspondence at Step 64. At Step 65, the reading unit 74 reads the information embedment “0”, when the distance is equal to or smaller than the threshold T, and reads the embedment information “1”, when the distance is greater than the threshold T.
When the extracted polygon is, as shown in
When the extracted polygon, as shown in
According to the present invention, by changing the range of the value of embedment information, it is also extensible to multiple values other than binary (“0” and “1”), similar to Embodiment 2.
The present embodiment can be changed as follows.
(1) Embedment information (“0”, “1”) may be changed.
(2) Although the value determining the range of the value of the embedment information is set to “1”, the value can be substituted by an arbitrary value that is equal to or greater than “0”, instead of “1”.
(3) The range of the value which the distance can take can be changed. In other words, the arrangement information of the geometrical element can be changed.
The extracting unit 81 inputs vector data including definition information of a polygon, and extracts a plurality of vertices which constitute the polygon.
The inserting unit 83 determines insertion points (the number is N; N=1 in the present embodiment) which should be inserted in between two vertices adjoining each other among the plurality of vertices that are extracted by the extracting unit 81. For example, when the polygon is a quadrangle, since the number of vertices of the polygon is “4”, the number of the insertion points is “4”.
The embedding unit 84 embeds all the insertion points that are determined by the inserting unit 83 in the extracted polygon.
Next, referring to
It is assumed that the polygon before embedding is a quadrangle P1P2P3P4 shown in
As shown in
In the present embodiment, a case where the center of gravity G1 and the center of gravity G2 are in agreement corresponds with a case where a value of embedment information is “0”. In addition, in order to secure an acceptable range against an error etc., a small threshold T (for example, T=1) is introduced. When the distance between the centers of gravity G1 and G2 is equal to or smaller than the threshold T, it is considered that the two centers of gravity G1 and G2 are in agreement.
On the other hand, in
In
At Step 71, the inserting unit 83 checks the value of the embedment information. When the value is “0”, the processing moves to Step 72, and when the value is “1”, the processing moves to Step 73.
At Step 72, for example, as shown in
At step 73, for example, as shown in
At Step 74, the embedding unit 84 embeds the insertion points, which are determined by the inserting unit 83, into the extracted polygon, and outputs the result as the embedment information embedded vector data.
In the present embodiment, when inserting the insertion points, the insertion points are arranged on straight lines which connect each of the point P1 and the point P2, the point P2 and the point P3, the point P3 and the point P4, and the point P4 and the point P1, therefore, a change of shape from the data of embedment information to the original data can be avoided.
The present embodiment can be changed as follows.
(1) Although one new point is inserted in between each pair of extracted adjoining vertices, the present invention is not limited to the case. If the number of N of the insertion points is greater than “1”, it may cope with a case where the embedment information is multi-valued.
(2) As the correspondence regarding embedding, the distance between the center of gravity G1 and the center of gravity G2 is set to be equal to or smaller than the threshold T when the embedment information “0” is embedded, and the distance between the center of gravity G1 and the center of gravity G2 is set to be greater than the threshold T when the embedment information “1” is embedded. However, when the embedment information “0” and “1” are exchanged, the same effectiveness can be acquired. Moreover, it is set that the threshold T=1, but the threshold T is not limited to the value.
(3) Regarding embedding processing, when the embedment information “0” is embedded, the insertion point Qi is inserted in each of the middle points of the point 1 and the point 2, the point 2 and the point 3, the point 3 and the point 4, and the point 4 and the point 1. When the embedment information “1”, is embedded, the insertion point Qi is inserted in a place shifted from the middle point. However, the present invention is not limited to the case.
The extracting unit 91 inputs embedment information embedded vector data (one that the embedment information is embedded according to Embodiment 7), and extracts a plurality of points of the polygon from the vector data.
The information reading unit 92 reads the embedment information that is embedded based on the plurality of points extracted by the extracting unit 91.
A classifying unit 93 classifies the plurality of points extracted by the extracting unit 91 into a first set and a second set. The classifying unit 93 determines the center of gravity of a first figure that is constituted by the plurality of points belonging to the first set, and the center of gravity of a second figure that is constituted by the plurality of points belonging to the second set. In more detail, the classifying unit 93 gives the consecutive numbers to the plurality of points extracted by the extracting unit, and classifies the plurality of points extracted by the extracting unit according to whether the consecutive numbers are even or odd. The above-mentioned classification is possible because the number of the insertion points is N=1, as in Embodiment 7. When the number N is set to be greater than “1”, the plurality of points extracted from the extracting unit are classified into the first set, the second set, . . . , and (N+1)th set.
The distance-between-centers-of-gravity calculating unit 94 calculates the distance between the center of gravity of the first figure and the center of gravity of the second figure.
The reading unit 95 reads the embedment information based on the distance calculated by the distance-between-centers-of-gravity calculating unit 94.
At Step 81, the classifying unit 93 gives the consecutive number M (M=1, 2 . . . ) to each of the plurality of vertices. At Step 83, the classifying unit 93 classifies these vertices into two vertex groups according to whether the consecutive number M is even or odd. One of the vertex groups is a set whose elements are the vertices in Embodiment 7, and the other one is a set whose elements are the insertion points in Embodiment 7.
At Step 84, the classifying unit 93 considers a polygon composed by a vertex group belonging to one set as a first polygon, and a polygon composed by a vertex group belonging to the other set as a second polygon. Then, the classifying unit 93 outputs the information of the first and second polygons to the distance-between-centers-of-gravity calculating unit 94.
At Step 85, the distance-between-centers-of-gravity calculating unit 93 obtains the centers of gravity of the first and second polygons, calculates the distance between the centers of gravity (Step 85), and outputs the distance to the reading unit 95.
At Step 86, the reading unit 95 compares the calculated distance with the threshold T in magnitude. When the distance is equal to or smaller than the threshold T (refer to
According to the present embodiment, there is the following effectiveness.
(Effectiveness 1) Since the information reading uses the embedment information independent of rotation operation, reading embedment information can be performed even from the vector data in which the rotation operation is applied.
The present embodiment can be changed as follows.
(1) Although classification is made into two sets according to the classification of the remainder (even or odd), the classification is not limited to the case.
(2) Although it is defined that the threshold T=1, the threshold is not limited to the value.
According to the present invention, the embedment information can be embedded by inserting a new point on the polygonal side, with suppressed shape change of original data. Operating the number of points constituting a polygon, the number of the points not being dependent on rotation operation, allows correct reading of the embedment information from vector data of which rotation operation is applied or from vector data for which the original data is not available.
Next, referring to
It is assumed that a system illustrated in
A GPS antenna 205 of the car navigation device 200 communicates with geostationary satellites, and inputs information in order to know the current location and direction. A display unit 201 displays the current location, the direction, surrounding routes and buildings, etc. Since the direction and the location of an automobile, in which the car navigation device 200 is installed, change variously, map data that is read out from the legal recording media 100 frequently receives the rotation operation, and is displayed on the display unit 201 in an understandable manner as it is shown in FIG. 31(a). A button 202 and a cross shaped pad 203 correspond to an operation input unit 216 shown in
The car navigation device 200 is mounted with an input/output port 204, and can communicate with an external device (for example, the personal computer 230 etc.) via the input/output port 204. Even if such a port is not prepared, since the infringer may destroy a part of the car navigation device 200 and copy the data of the legal recording media 100 forcibly, it is assumed that the port is prepared here.
As shown in
A control unit 210 controls each element of the car navigation device 200 according to the flowchart of
An information embedding device 213 and an information reading device 218 may possess a structure according to any of Embodiments from 1 to 7. In the present embodiment, embedment information shown in
A car navigation processing unit 211 performs car navigation processing. Since the present invention does not possess features of the car navigation processing itself, the detailed explanation related to the car navigation processing is omitted.
A temporary memory unit 214 is composed by RAM etc., and saves the data which the control unit 210 requires for processing.
A hash value calculating unit 219 inputs a value from the control unit 210, obtains a hash value for the inputted value using a hash function, and returns the obtained hash value to the control unit 210.
An interface 215 mediates communication between the control 210 and an external device. In the example of
Next, referring to
First, as mentioned above, the embedment information of the present embodiment is multi-valued data shown in
As shown in the upper part of
As shown in the middle part of
As shown in the lower part of
The inspector acquires a value indicating the copyright holder 1 as the copyright holder information of the illegal recording media 250 and the illegal paper media 251 from the first bit area of the embedment information that is read out, and confirms the copyright holder. Moreover, whether the value of the second bit area is the hash value of the value of the first bit area is checked. If it is the hash value, the illegal recording media 250 and the illegal recording media 251 are judged that they have been sold legally. However, since the identification value of the car navigation device 200 (the device 1) is embedded in the illegal recording media 250 or the illegal paper media 251, it is judged to be an illegal copy. In addition, it can be confirmed that the illegal copy is made by using the car navigation device 200 (the device 1). Thereby, the responsibility of the infringer who uses the car navigation device 200 (the device 1) can be pursued.
Next, referring to
At Step 91, the control unit 210 reads map data from the recording medium 100, and reads the value of the first bit area and the second bit area using the information reading device 218.
At Step 92, the control unit 210 checks whether the value of the second bit area is in agreement with the identification value which the device identification value holding unit 212 holds. When it is in agreement, the processing moves to Step 96. When it is not in agreement, the processing moves to Step 93.
At Step 93, the control unit 210 makes the hash value calculating unit 219 determine the hash value of the value of the first bit area, and checks whether the hash value and the value of the second bit area are in agreement (Step 94). When it is not in agreement, at Step 95, the control unit 210 warns that the recording medium 100 under processing is an illegal copy, and then the processing is discontinued. Thereby, the recording media that is illegally copied can not be used practically. When it is in agreement, the processing moves to Step 96.
At Step 96, the control unit 210 reads necessary map data, and stores the read map data in the temporary memory unit 214. At Step 97, the control unit 210 embeds the embedment information of which the second bit area is the device identification value in the map data, and stores the embedded map data in the temporary memory unit 214 (Step 98).
Then, the control unit 210 outputs embedded map data to the car navigation processing unit 211, and performs processing of navigation. At Step 99, the car navigation processing unit 211 acquires information from the GPS antenna 205, and performs processing of navigation based on the embedded map data. At this time, the embedded map data frequently receives a rotation operation.
At Step 100, the control unit 210 inputs the processed result from the car navigation processing unit 211, and makes the display unit 201 display the processed result via the interface 215. Thus, since the embedded map data is outputted to the interface 215, even if the map data is transferred to the personal computer 230 via the input/output port 204 connected to the interface 215, the transferred map data is the map data which the device identification value is embedded. Therefore, even if the illegal recording media 250 and the illegal paper media 251 are acquired by using the personal computer 230, the infringer ends up leaving, without knowing, traces that the infringer has performed the illegal copy in the illegal recording media 250 and the illegal paper media 251.
At Step 101, the control unit 210 repeats processing after Step 96.
Generally, when the illegal copy is performed by the paper data media, it is often unclear for an apparently pirated edition and an original to be known whether they are an illegal copy or not. It is because, when printed, the map data has undergone the rotation operation from the state of original in most cases.
However, when processing as shown in
The present invention can be suitably used in information processing devices which deal with vector data, such as map data.
Cited Patent | Filing date | Publication date | Applicant | Title |
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US20020122564 * | Oct 23, 2001 | Sep 5, 2002 | Rhoads Geoffrey B. | Using embedded identifiers with images |
JP2001078019A * | Title not available | |||
JP2001209780A | Title not available | |||
JP2001339597A | Title not available | |||
JP2002152486A | Title not available | |||
JP2002209086A * | Title not available | |||
JP2002300374A | Title not available | |||
JP2003067776A | Title not available | |||
JP2003101751A | Title not available |
Reference | ||
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1 | * | Machine translation for JPN 2001-078019. |
2 | * | Machine translation for JPN 2002-209086. |
Citing Patent | Filing date | Publication date | Applicant | Title |
---|---|---|---|---|
US8243070 * | Apr 18, 2008 | Aug 14, 2012 | Adobe Systems Incorporated | Triangulation for accelerated rendering of polygons |
U.S. Classification | 382/100 |
International Classification | H04N1/387, G06K9/00 |
Cooperative Classification | G06T1/0064, G06T2201/0051 |
European Classification | G06T1/00W6G |
Date | Code | Event | Description |
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